The major project for the coming year will be the identification of the different types of propriospinal interneurons with ascending axons in the isolated spinal cord of the lamprey. These cells will be marked morphologically by intracellular injection of peroxidase, and they will be tested for synaptic interactions with other identified neurons by intracellular stimulation and recording. The interneurons will be surveyed for phasic potential changes or synaptic drive during swimming activity induced by D-glutamate in the bathing fluid. A second project will be characterization of trigeminal reflexes and synaptic connections of trigeminal motoneurons in the lamprey.